Recoil operated automatic gun



United States Patent "4 RECOIL OPERATED AUTOMATIC GUN Alexander Stone McColl, Kalamazoo, Mich. `Application October 24, 1952, Serial No. 316,571

1 Claim. (Cl. 89-163) This invention relates to improvements in recoil operated automatic gun.

The principal objects of this invention are:

First, to provide a recoil operated automatic weapon that is simple and inexpensive to manufacture while still being entirely effective.

Second, to provide a recoil operated gun in which the barrel and the bolt move rearwardly under the recoil action of the gun and are automatically unlocked by rotary motion of the barrel.

Third, to provide a recoil operated gun in which the breech and barrel remained in closed position for a substantial period after the explosion of the cartridge in the gun and are thereafter automatically unlocked for retraction of the breech by rotary movement of the barrel.

Fourth, to provide a recoil operated automatic weapon in which the barrel may be easily removed for repair or replacement.

Fifth, to provide a recoil operated automatic weapon having a relatively few number of operating parts.

Other objects and advantages of the invention will be apparent from a consideration of the following description and claim. The drawings of which there is one sheet illustrate a highly practical form of the gun.

Fig. l is a fragmentary side elevational view of an automatic gun embodying the invention.

Fig. 2 is an enlarged fragmentary side elevational view of the gun partially broken away in longitudinal cross section to illustrate the features of the invention.

Fig. 3 is an enlarged fragmentary elevational view of the gun similar to Fig. 2 but illustrating the action in partially retracted position.

Fig. 4 is a fragmentary transverse cross sectional view through the receiver and bolt in the retracted position of the vbolt taken along the plane of the line 4-4 in Fig. 3.

Fig. 5 is a fragmentary horizontal cross sectional view through the front barrel retaining nut taken along the plane of the line 5--5 in Fig. 2.

Generally the gun embodying the invention includes a stock 1 to which a tubular receiver 2 is pivotally connected by the bolt or pin 3. A ferrule 4 fastened around the receiver is one means of forming the pivotal connection to the receiver. A catch indicated generally at 5 releasably locks the rear end of the receiver to the stock. A closure 6 c'loses the rear end of the receiver and forms au abutment for the recoil spring 'l housed in the rear end of the receiver.

Slidably mounted in the forward end of the receiver 2 is the barrel 8. The rear end of the barrel is guided and aligned by the forward end of the receiver as is apparent in Figs. 2 and 3. Rearwardly from the rear end of the barrel 8 the side of the receiver 2 is provided with an oblong aperture or slot 9 through which spent cartridges are ejected. A magazine 10 is mounted on the under side of the receiver below the ejector opening and a forward hand grip 11 is secured under the forward end of the receiver. The gun is red by operation of the trigger 12 and the details of the trigger action and the details of the magazine feed into the receiver are of no importance to the present invention and so are not illustrated in greater detail.

The present invention relates to the structure for controlling the locking and unlocking of the bolt to the barrel. The bolt in the present instance is illustrated as a cylindrical member 13 that is axially slidable within the receiver. The bolt is provided with ribs 15 that are engaged in slots 16 on the interior of the receiver to restrain the bolt from rotation within the receiver. A bolt having a hand knob 17 projects from the bolt 13 through a slot 1% in the side of the receiver for hand operation of the boit. The forward end of the bolt is provided with a breech portion 19 of reduced diameter that is adapted to project forwardly into the chamber 20 formed in the rear end of the barrel. The breech portion may be provided with an extractor finger 2l that is received in a slot provided therefor at 22 in the rear end of the barrel. The breech portion 19 is further provided with oppositely projecting pins or lugs 23 that lockingly engage the bolt with the barrel.

The barrel as previously described is axially slidable within the forward end of the receiver. The forward end of the receiver has a spiral slot 24 formed therein that extends forwardly through the forward end of the receiver. A pin or lug 2S projecting from the barrel 8 is received in the slot 24 so that rearward motion of the barrel causes the barrel to rotate within the receiver. The rear end of the barrel is provided with rearwardly opening angu- 'larly shaped bayonet slots 26 that are arranged to receive the previously mentioned lugs 23 on the breech portion of the bolt. t will be apparent that initial rearward motion of the bolt and barrel in locked relationship will rotate the barrel and the bayonet slots 26 until the lugs 23 are uncovered and permitted to move rearwardly from the barrel. The rear end of the spiral slot 24 then forms a stop for the pin 25 that stops further rotation and rearward motion of the barrel. The bolt continues rearwardly under the inertia of its initial motion against the compression of the recoil spring 7 to actuate the cocking and loading mechanism of the gun. The barrel remains in its retracted and rotated position so that when the bolt is returned forwardly by the spring 7 the lugs 23 enter the open ends of the bayonet slots 26 and abut against the base of these slots.

The forward impact of the bolt and the pins 23 against the barrel 8 serves to drive the barrel forwardly and the engagement of the pin 25 in the spiral slot 24 causes the barrel to return to its initial unrotated position thus locking the pins 23 in the slots 26. In order to limit the forward movement of t e bolt and the barrel the forward end of the receiver is provided with a stop nut 27 that is engaged with threads 2S formed on the forward end of the receiver. The rear end of the nut 27 thus forms a stop for the pin 2S proiecting from the barrel. In order to prevent the tightening of the stop nut 27 from deforming the slotted forward end of the receiver and thus binding the barrel 8 a ring 29 is provided around the barrel between the nut 27 and the forward end of the receiver. The ring 29 has a spacer lug 30 that projects rearwardly into the forward end of the slot 24. The bolt is of course provided with a ring pin 31 of suitable design that is capable of firing the cartridge which is indicated at 32.

The foregoing construction has a very few parts that are easily manufactured and assembled and it is pointed out that the barrel 8 can be easily removed for repair or replacement.

Having thus described my invention, what is claimed to be new and is desired to be secured by Letters Patent, is:

A recoil operated gun comprising, a relatively fixed receiver having `a tubular forward end, a barrel slidably mounted in the forward end of said receiver and projecting forwardly therefrom, the forward end of said receiver having a spiral cam slot formed therein and extending through the forward end thereof, the forward end of said slot having an axially straight portion, a ring disposed around said barrel and having a lug projecting into the-forward vend of said slot, a nut threaded on the forward `end of said receiver, a pin carried by said barrel and extending into said slot, the rear end of said barrel having radially opening .axially and circumferentially extend ing right angled slots formed therein and opening to the rear end thereof, a bolt slidably mounted in said receiver and having a breech portion on its forward end coacting with`the'end'of said barrel, lugs projecting radially from said bolt and lockingly engageable in said angled slots,

a rib projecting from said bolt and sliding in a vgroovein 'said vreceiver to prevent rotation of said bolt, and a spring engaged with said bolt andv biasing said bolt forwardly, said barrel being free to move and stop in said receiver solely under the control of said bolt and said pin in said cam slot.

References Cited in the Ile of this patent UNITED :STATES PATENTS 

